No Audio when streaming via Airplay to Apple TV to Beam via Airplay 2

We bought a Sonos Beam to replace our B&O Beolit '12 Airplay enabled speaker in the living room. We are using an Apple TV (4. gen) connected to a projector. So far the audio of video content was streamed to the Beolit via Airplay from the Apple TV. We liked this because of the cablelessness. Now Airplay 1 wasn't always that stable hence the upgrade to the Beam beacause of Airplay 2 A/V sync capabilities. Now we have a problem that content when streamed via an Macbook e.g. from Youtube via the Airplay option in Safari (same with just airplay monitor sync or Beamer app) to the Apple TV we have image but no audio anymore. Tried to create a little table below to explain the problem. #4 is the problem with no audio. Is this a general Airplay 2 problem (same with Homepod?) or some problem with the Sonos implementation of Airplay 2?

The cause of the problem is the following: the Apple TV can ONLY AirPlay audio to another device if it is the source of the media. You can’t AirPlay from a Mac to an Apple TV and at the same time have AirPlay audio on the SONOS Beam streamed by the Apple TV. On the MacBook try to select the Apple TV AND the SONOS Beam as output devices. I don’t have a current Mac to test your situation but if it doesn’t work you will need to stream audio from the projector to the Beam with a cable to see content from the MacBook.

I have tested my suggestion. It won’t work. AirPlay can’t send audio to one device and video to another device. With my suggestion, video would continue to play on the MacBook and audio would be sent to the Beam AND to the Apple TV. The audio sent to the Apple TV from the MacBook would be output through HDMI to the projector.

I have tested my suggestion. It won’t work. AirPlay can’t send audio to one device and video to another device. With my suggestion, video would continue to play on the MacBook and audio would be sent to the Beam AND to the Apple TV. The audio sent to the Apple TV from the MacBook would be output through HDMI to the projector.

I have tested my suggestion. It won’t work. AirPlay can’t send audio to one device and video to another device. With my suggestion, video would continue to play on the MacBook and audio would be sent to the Beam AND to the Apple TV. The audio sent to the Apple TV from the MacBook would be output through HDMI to the projector.

The audio output options you choose on an Apple TV ONLY work if it is the SOURCE of the media you are playing. If you are using AirPlay to send video or audio to it, either from a Mac, an iPhone or an iPad only the HDMI port will be active for audio output. If you have set it up to send audio to a SONOS speaker or an Apple AirPort Express, if you are sending audio or video to the Apple TV with AirPlay, there won’t be audio output to this devices.